>>2518321Down is roughly 5 times as light as wool for the same insulation.
I can see the appeal of a nice looking "old" live action role playing gear set with a wool blanket to have fun with, but it's not "the best".
Which is why wool was replaced by down items like the arctic robe as soon as they came up in the late 19th century.
More reading
http://woodtrekker.blogspot.com/2014/09/long-term-wilderness-living-blanket-vs.html